This elementary article could have, and should have, been written and published long ago. The condensation of water vapor to form dew or frost on solid natural and artificial surfaces is a commonly observed natural phenomenon. It is well understood that the latent heat released as water vapor condenses slows the radiational cooling of these surfaces during the diurnal temperature cycle.

There can be little doubt that the ability of atmospheric water vapor to condense (releasing its significant latent heat of condensation to its environment) limits the minimum possible temperature of the common diurnal temperature oscillation. The ability of this same atmospheric water vapor (and certain other atmospheric gases) to absorb portions of the radiation emitted by the earth’s surface has nothing to do with this minimum temperature limitation.










